1. Field
The present invention relates to a hydraulic unit of an electronic control brake system, and more specifically, to a hydraulic unit of an electronic control brake system for controlling brake pressure in a brake system through an electronic control.
2. Description of the Related Art
An electronic control brake system for efficiently preventing a slip that may be generated at the time of braking of a vehicle, sudden unintended acceleration, or sudden acceleration, generally includes not only a booster for a brake system of a vehicle, a master cylinder, and a wheel cylinder, but also a hydraulic unit for controlling a braking hydraulic pressure and an electronic control unit for controlling the hydraulic unit.
Recently, a system for obtaining a more powerful and stable braking force has been proposed, for example, an integrated dynamic brake (IDB) system has been proposed. The proposed IDB system generates a stable and powerful braking force by integrating a master cylinder, a booster, and an electronic stability control (ESC).
This IDB system includes a pressure supplying device which operates a motor by outputting an operation of a brake pedal as an electrical signal through a pedal displacement sensor and converts rotational force of the motor into linear motion; and a hydraulic unit having a modulator block having a plurality of valves to control a brake operation by receiving hydraulic pressure using a force generated by the pressure supplying device. Herein, the hydraulic unit includes a plurality of inflow/outflow valves, a shut-off valve, a switching valve, a check valve, a pressure sensor, a pedal simulation valve, and the like, to control a braking hydraulic pressure transmitted towards wheel cylinders each provided in vehicle wheels, and the these components are compactly installed in the modulator block formed of aluminum. Also, a plurality of valve bores, a port for connecting the master cylinder with the wheel cylinder, and a plurality of passages for guiding a direction of hydraulic flow are processed to compactly install the plurality of components in the modulator block.
However, since a conventional hydraulic unit has an unnecessary dead space other than a space in which a plurality of components are arranged, an improved arrangement structure of the components is required. Since a modulator block increased in size is arranged, a size and weight of a hydraulic unit is increased, and thus there is a problem of increasing costs.
Also, a lack of symmetry between two hydraulic circuits formed in the modulator block generates a pressure deviation, so there is a problem of decreasing durability due to generation of noise and vibration.
A hydraulic unit of an electronic control brake system according to an embodiment of the present invention can minimize a size of a modulator block by arranging passages, formed in the modulator block, in two layers, and minimize a pressure deviation by making a structure of two hydraulic circuits symmetric to each other.